On the Register tab, log each sample: its number, the date collected, the patient, the test requested from a dropdown, and a result status. When you report it, enter the date reported and the turnaround days fill in for you. The Pending tab lists every sample not yet reported, oldest first, with the days it has been waiting, so nothing is forgotten. Test Counts breaks the work down by test type, with how many are reported, how many pending, and the average turnaround for each.
Yellow cells are the only ones you type in; the rest is locked formulas. Because the register holds patient names and results, keep it on a device only your staff can reach, and in Google Sheets share it with named people, never a public link. Opens in Excel, WPS or Google Sheets, so you can keep it on the bench or on your phone.